Computational Fluid Dynamics in ۳D-Printed Scaffolds with Different Strand-Orientation in Perfusion Bioreactors

Bone tissue engineering strategies use fluid flow dynamics inside ۳D-scaffolds in perfusion, bioreactors mechanically stimulate cells in these scaffolds. Fluid flow dynamics depends on the bioreactor’s inlet flow rate and ۳D-scaffold architecture. We aimed to employ a computational evaluation to assess fluid dynamics in ۳D-printed scaffolds with different angular orientations between strands in each layer inside a perfusion bioreactor at different inlet flow rates. ۳D-printed cubic scaffolds (۰.۶×۰.۶×۰.۶ cm; total volume ۲۱۶×۱۰-۳ cm۳) containing strands (diameter ۱۰۰ µm) with regular internal structure and different angular orientation (۳۰°, ۴۵°, ۶۰°, and ۹۰° between strands in each layer) were used for modeling. The finite element method showed that the perfusion bioreactor’s inlet flow rate (۰.۰۲, ۰.۱, ۰.۵ mL/min) was linearly related to average fluid velocity, average fluid shear stress, and average wall shear stress inside ۳D-printed scaffolds with different angular orientation (۳۰°, ۴۵°, ۶۰°, ۹۰°) between strands in each layer. At all inlet flow rates, strands at ۳۰° angular orientation increased average fluid velocity (۱.۲-۱.۵-fold), average fluid shear stress (۶-۱۰-fold), and average wall shear stress (۱.۴-۲-fold) compared to strands at ۴۵°, ۶۰°, and ۹۰° angular orientation providing similar results. In conclusion, significant local changes in fluid dynamics inside ۳D-printed scaffolds result from varying the degree of angular orientation between strands in each layer, and the perfusion bioreactor’s inlet flow rate. By decreasing the angular orientation between strands in each layer and increasing the inlet flow rate of a perfusion bioreactor, the magnitude and distribution of fluid velocity, fluid shear stress, and wall shear stress inside the scaffold increased. The average fluid velocity, average fluid shear stress, and average wall shear stress inside the scaffold within the bioreactor increased linearly with the inlet flow rate. This might have important implications for bone tissue engineering strategies using cells, scaffolds, and bioreactors.

Keywords:

Bone tissue engineering , Fluid flow dynamics , perfusion bioreactor , ۳D-printed scaffold , Finite element modeling , strand orientation